Better test scores through incentives

Alex Tabarrok points out some interesting stuff about education vouchers, but misses a key point.

First, that the test scores of the students in the public schools improved when vouchers gave the schools better incentives to perform. Second, at least some of the improvement comes from changes in how students are taught.

Emphasis mine. Test scores don't equate educational quality, or even learning. They just imply better test scores.

I'm all for vouchers, but I don't think these studies show anything particularly interesting. The true strength of vouchers is that it provides parents with the freedom to uncover which school provides the best quality, which in turn provides incentive to signal or actually improve quality. While this provides a bias in favor of children with resourceful parents (ie who have the time to research which schools are best), I think the freedom provided and improved incentives are worthwhile. Especially since there's currently no sane way for governments to improve schools by tinkering.